Projection screen

Abstract

A projection screen for forming an image by converting light pixel pulses from a digital projector comprises a three-dimensional sheet matrix made of a transparent composite. Functional inclusions for light-scattering, light-absorbing and luminescence of the light from the projector are distributed through the matrix thickness to thereby enable that the conversion of the light pulses into the image for direct perception by eyesight be performed throughout the volume of the matrix. The matrix thickness between the frontal and rear surfaces of the matrix is selected for digital image sources between an inter-pixel grid width and tenfold diagonal size of a pixel of a digitized image on the screen. The object of the invention is to reproduce identifying features of informational models of real objects in a wide angle of image perception under side lighting.

The invention claimed is: 
     
       1. A projection screen for forming an image by converting light pixel pulses from a digital projector, the screen including a three-dimensional sheet matrix made of a transparent composite, the matrix being defined by a frontal and a rear surfaces thereof, wherein functional inclusions for light-scattering, light-absorbing and luminescence of the light from the projector are distributed through the matrix thickness to thereby enable the conversion of the light pulses into the image for direct perception by eyesight to be performed throughout the volume of the matrix, the matrix thickness between the frontal and rear surfaces being for digital image sources selected between an inter-pixel grid width and tenfold diagonal size of a pixel of a digitized image on the screen. 
     
     
       2. The projection screen according to  claim 1 , wherein, in case of direct projection of images with reflection of projector light flow, a rear side of the screen has a light-reflecting coating with a reflection coefficient of 0.1 to 0.999, and a value of roughness on the reflecting surface is no more than ¼ of the violet light wavelength in the transparent matrix material. 
     
     
       3. The projection screen according to  claim 2 , wherein the light-reflecting coating is mirror-matt. 
     
     
       4. The projection screen according to  claim 3 , wherein a back side of the light-reflecting coating has an opaque coating absorbing the light emission that passed through the mirror-matt coating. 
     
     
       5. The projection screen according to  claim 1 , wherein the outer surfaces of the composite matrix have an anti-reflective coating. 
     
     
       6. The projection screen according to  claim 1 , wherein the frontal or frontal and rear outer surfaces of the matrix are satined with microlens, raster, prism or multi-spike structures having random distribution of sizes and/or directions of the structures extended in the surface plane and having a typical size of roughness cross-sections of no more than ¼ of the violet light wavelength in the transparent matrix material. 
     
     
       7. The projection screen according to  claim 1 , wherein a fine-dispersed light-scattering component in the form of aerogel, micro-spherules, micro-crystallites, powder and similar components or mixtures thereof of oxides of titanium, calcium carbonates or other white pigments with a typical size of not more than ⅕ of the width of gaps between discrete image elements at the screen is introduced into the volume of the matrix uniformly across the screen, and a total amount of these composite components in the matrix is selected so that they would cumulatively overlap at least 15% of the image area. 
     
     
       8. The projection screen according to  claim 1 , wherein a microdispersed luminescent additive having a typical time of afterglow from 0.02 to 0.3 seconds is introduced into the matrix, and a total amount of this additive is selected based on organoleptic criterion of image flicker invisibility at a projector projection frame rate. 
     
     
       9. The projection screen according to  claim 8 , wherein the microdispersed luminescent additive includes more than one luminescent additives characterized by a predominantly resonance luminescence and by a frequency selectivity with luminescent return maxima, wherein said maxima correspond to the standardized transmission frequency maxima of a color separation system of the projector. 
     
     
       10. The projection screen according to  claim 1 , wherein a fine-dispersed light-absorbing component in the form of fibers, powder, needle- or sphere-shaped nanostructures is introduced into the matrix to provide contrast and playback of black color, the total amount of said component per area of light flow overlapping being determined by the condition of preserving at least one third of a total useful light flow from the projector. 
     
     
       11. The projection screen according to  claim 10 , wherein the light-absorbing component is made of carbon fiber, including carbon fiber having nano-sized cross sections, wherein the fiber length is from 0.05 to 1.0 of the matrix thickness, and the ratio of the fiber length to its thickness is at least 10, the fibers being oriented along emission beams and across the matrix, and a typical distance between the fibers being from 0.01 to 1.5 of distances between the discrete elements of the projector image on the screen. 
     
     
       12. The projection screen according to  claim 1 , wherein the matrix is made of high-molecular polymeric materials in which polymer macromolecules are predominantly oriented along the course of light beams of the projector. 
     
     
       13. The projection screen according to  claim 1 , wherein the screen has a cylindrical or ellipsoidal shape, with radii in the horizontal and vertical cross-section planes being from the minimum viewing distance to infinity. 
     
     
       14. The projection screen according to  claim 1 , wherein the front surface of the screen is covered with light-absorbing fibers oriented perpendicularly to the plane of the screen surface. 
     
     
       15. The projection screen according to  claim 1 , wherein the frontal surface of the screen is covered with light-absorbing fibers oriented predominantly along the course of projector light beams in case of a rear projection screen or along the median of the courses of projector direct and inverse beams in case of a retroreflective screen of front projection. 
     
     
       16. The projection screen according to  claim 1 , wherein the functional irregularities are distributed across the matrix thickness layer-wise and/or with a continuously varying concentration within the layer or throughout the whole matrix thickness. 
     
     
       17. The projection screen according to  claim 1 , wherein the screen is provided with a light valve layer of controlled light flow transmittance. 
     
     
       18. The projection screen according to  claim 1 , wherein the screen is provided with a system for automatic adjustment of light transmission depending on brightness of an external illumination. 
     
     
       19. The projection screen according to  claim 1 , wherein an optical density maximum of the light-absorbing inclusions is located in an area not further from the front screen surface than a concentration maximum of light scattering inclusions is located in the matrix.